1. Department of Orthopedic Trauma, Affiliated General Hospital, Ning Xia Medical University, Yinchuan, China;
2. Hebei Province People's Hospital, Qian'an, China;
3. Ning Xia Medical University, Yinchuan, China;
4. State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing, China